Abstract: A remote keyless entry system particularly suited for preventing access to unauthorized individuals by securely encrypting messages transmitted from a remote transmitter to a receiver. A unique encryption algorithm is used to generate a multibit message having a pseudorandom number, key code and transmitter identification code (ID) encrypted within. The encryption algorithm generates said multibit message as a function of a pseudorandom number generator, a fixed key code table, ID and a switch, e.g., command, code. A receiver can decrypt the message to obtain the switch code and will respond thereto only if the message originated from an authorized transmitter, i.e., if the received pseudorandom number, key code and ID match those stored within the receiver.